Conventionally, an electric power converter for converting DC power from a battery into AC power is mounted in electric vehicle, hybrid vehicles, or the like, for driving a motor for vehicle running.
The electric power converter includes a semiconductor module with a built-in semiconductor element.
The semiconductor module generates heat due to a controlled current flowing through the semiconductor element.
When a semiconductor module with a large capacity is used, a cooler with a high cooling performance is required because there is a tendency that heat generation in the semiconductor module increases.
Furthermore, when designing this type of electric power converter, there is a need to construct an electric power converter that is small in size and has excellent vehicle mountability.
Therefore, an electric power converter constituting a stacked semiconductor unit by alternately stacking semiconductor modules and cooling tubes for cooling the semiconductor modules is disclosed in Japanese Patent Application Laid-Open Publication No. 2009-261125.
A stacked-type cooler in which a plurality of cooling tubes are stacked is used in the electric power converter.
In the cooler, in order to press-contact the plurality of cooling tubes and the plurality of semiconductor modules in a stacking direction, it is configured that a pressure member that is elastically urged by a spring member presses an outer cooling tube positioned at one of outer sides in the stacking direction.
Thus, the semiconductor modules can be cooled from both sides in the stacking direction, thereby improving the cooling efficiency of the semiconductor modules.
Further, the stacked semiconductor unit is configured so as to sandwich a heat dissipating body used for cooling electronic components (heat dissipating bodies) other than the semiconductor module in a space between two adjacent cooling tubes.
The heat dissipating bodies are connected to heat-receiving bodies that receive heat from the electronic components via heat pipes.
However, the electric power converter disclosed in Publication No. 2009-261125 has the following problems.
Extra cooling tubes for sandwiching the heat dissipating bodies are required in the stacked-type cooler.
Therefore, when a flow rate of a cooling medium in the cooler is constant, part of the cooling medium may flow into the extra cooling tubes.
For this reason, the flow rate of the cooling medium flowing through the cooling tubes for cooling the semiconductor modules is reduced.
As a result, a problem that the cooling performance of the cooler to the semiconductor module is lowered may occur.
Further, in order to cool electronic components different from the semiconductor modules, there is a problem that exclusive components such as the heat dissipating body, the heat-receiving body, the heat pipe, or the like becomes necessary in addition to the stacked-type cooler.